Process of and means for preparing molds



Jan. 24, 1928. 1,657,444

c. K. PRINCE PROCESS OF AND MEANS FOR PREPARING MOLDS Filed Oct. 6, 19265 /3 6 2a erzo 76 Li 67166 ill , Patented Jan. 133218.

unrrno STATES 6.71.. ARENCE PATENT ()FFICE.

ESTBATOB 0F SAID OLABEI-ICE K. ERINGE, DECEAESED.

PROCESS OF AND MEANS FOR PREE'ARING MOLDS.

Application filed October 6, 1926. Serial No. 139,843.

This invention pertains to the art of preparing molds for use in castingmolten materials, fo example, iron, and relates more particularly to aprocess of reinforcing green sand prints, to a mold having such areinforced. print; and to a reinforcing or retaining :vice for suchprints.

in castin thin-walled cored articles, of which a rad or section isherein specifically referred to by way of eir'unple, it is of vitalimportance to support the core accurately and iirnilv within the moldcavity, since the movement of the core relatively to the sides of themold cavity results in the production of a casting ha thin spots orholes its walls, it worthless tor the purpose for which it was designed.Khan the casting; is to have an opening or openings leading to itsinterior, the core must be united to the side wall of the cavity at thepoint where the opening is to e formed, h member or print which unitesthe core and cavity wall may bean integral projection upon the core,termed a core print, or it may be a protuberance upon the wall of themold proper, 1n the latter case being commonly known as a green sandprint. "il hichever type of print be employed, such print shouldconstitute reliable guide means to facilitate the location of the corewithin the ,mold cavity and should also furnish an adequate and firmsupport for adjacent portions of the core. Those parts the core winchare remote from the print or prints, are supported in proper positionrelative to the sides of the mold cavity by means of metallic supportsor chaplets, the number of such chaplets varyingwith the length and sizeof the core t he supported. When the core is of any c crable length, theaccurate and careful g'ilacing of the necessary number of chapletsconsumes considerable time, while, moreover, as the c liaplets areembedded in the finished casting and can not again be used, their costis a considerable item of expense to the founder.

l i hiie core prints are commonly used, they are open to certain seriousobjections, for exan'iple, when they are of small diameter or ofsubstantial length they tend to warp during baking so that they nolonger accurately coiitorm to the position of the desired openin thecasting. Such core prints turinadequate assistance to the molder inplacing the core, and if warped or twisted may greatly delay him in hisefforts to produce accurate work. Furthcrn'iore, in order to provide therequisite draft in making the core, it is necessary to make the coreprint taper outwardly from the body of the core. This produces anopening in the casting which tapers outwardly, although in many cases,for example, in the manufacture of radiator sections, itis desirable tohave the opening in the casting taper inwardly, and thus it a core printbe used, an excessive re moval of metal by machining is necessary inorder to provide an opening of the desired taper in the casting.

[is compared with the core print, the green sand print would have noneof the above disadvantage since, first, it could be produced with greataccuracy by the more provision of an openingin the pattern to receivethe sand, and as the mold is not baked, such green sand print would notwarp or twist; secondly, it is comparatively easy to provide the corewith a shallow socket for the reception of the inner end of such a greensand print, since such a socket is but little affected by baking andthus retains the accuracy of location originally imparted to it. Thusthe molder could locate" the core accurately and quickly merely bysetting the socket of the core over the green sand print; thirdlyv thetaper of a green sand print in inward, like that of the open ing desiredin the casting, so that but little machining of the casting would berequired if a green sand print were employed.

Thus, the green sand print would possess several desirablecharacteristicsnot found in the core print, but heretofore it hasgenerally been considered impractical, under many conditions at least,to use the green sand print for this purpose on account of itsfriability and lack of strength. I have new discovered a )rocess ofmolding in which all of the advantages of the green sand print may beavailed of and to: this endhave devised a reinforce device or retainerfor such a green sand, print, by. means of which the print may be madesufficiently strong and still to retain the shape originally in'ipartedto itduring molding, and by the use of this rig-id green sand print I amable to posi ion t 1c core so much more accurately than is usual asgreatly to improve the quality of the castings. Incidentally, the

practice ojtithis new process and the employment of thenew retainerdevice permits a substantial reduction in the number of thechapletsemployed, since the reinforced grecn sand prints,furnish sorigid a support for the core that but little further support isnecessary. in the number of chaplets required is sufficient to ofl setthe cost of thenew-reintorce device.

In the accompanying;drawings I have illustrated-certain steps in myimproved process as applied h way of example to the productionot aradiator section and have also illustrated by improved reinforce Fig.6is an elevation, partly in vertical. scctionand partly broken away of aradar,

torsection as itappears when removed from the mold;

Figzt is a 1' .iginentary section of a easting made-in accordance withthe present invention and i illustrating the step of machining theopening therein;

Fig. 7 is a tragn'ientary vertical section illustrating a usual lnodefotconnecting a pair of radiator sections; and

Fig. 8 is a. if'aginentary vertical section through a mold, showing thecasting therein and illustrating the results of using a core printrReferring to the drawings, the numeral 1 designates a pattern, hereinillustrated as that for making ani ordinary ra tliator section such asis used in inaking huilt-up radi a tors for steam or hot-Waterheating.The pattern is shown as restii'i r upon -a plate or hottom hoard i2,uponavhich is placed-one inenil'ier 3 ol a two-part umlding-llask.

\Vhile it is immaterialWhether this he con-- sidered as the bottom ortop meinher ol: the 'tlafsltait is for convenience hereinafter referredto asthe hottoin ineinheri- In accordance with the present inventionthepattern-1 isiprovided atsuitahlc points with cavitieset, each of thedesireddiameter and dept-lito receive a portionol? thenolih in'g: sandto lorm ;a green sand print, Such printa produce opeiiings indhewasting, and in the manufacture ofradiator sectlons-itns desirabletogproduce'an; open ng at hoth ends o'lf-tlie--sect-ion aml atmzch sideo-lihe In many Lcases the.Jcduetion latterito receive the llllltlllllilor other device cn'iployed tor uniting adjacent sections.

In accordance with the present invention, hetore-einlicddii if thepattern in sand, l: in troduce a print reinforcing; device into each ofthe cavities -:l. llteitcrrin to lii s. I} and -.l, I illustrate apreferred term of such rehe force device. As herein illustrated thisrcinl orcedevice [I is a cup-lilie structure, pre i erahly taperingFY0111 one end to the other, androinprising a generally(j/illitll'ltftll wall portion 7 preferably having at its smaller end aninwardly directed annular flange and having anchoring tabs 9 projectingfrom its'uppcr end. its hereslmwn, toun such tabs are provided, hut-theexact numher is immaterial. i

Preferably this reinforce device made i a stamping operation (ll'OlllSllQQll inatcrial and in order to ju'ovidc the nece sary depth of cupIprefer to slit the material as indicated at10, although I contemplalothat it tlieniaterial, heo't' suliioient ductility such slittin inav hedispensed with.

I also pro. .1' to employ perforatedimate rial in making this retainer,sineesuch per-i iterated material possesses sutlicient Htlll Ilu-ls forthe puiposeu'hile at the same time it contains much less material thanitmade of inuiertor'ate sheet nuderial. Thus it has less tendency to cooland sin'lace harden i llainolten iron which comes into coiitact therewith. While-,-as just stated, the. rot-liner may heniade of perforatedsheet metal, ll contemplatethatit might he made from a sheet-or \vireinesh i'naterial andfll. also rontemplate that -1naterial other thanmetal a l a lie en'iployed to advantageunder some cii" cui'nstances.

The-retainer is prel erahly of, such dimensions and shape as tolitsnugly .u'ithin the oi'ienings oftho pattern, thus termin in.

effect a lining tor the o lieniu r. the lower edge -12 oi theretaii'ierseating uponwthc bottom otthe opening, vhile the uppec value11 of the retainer is suhstantiallv flush with the upper edge ot theopening. Tlheamolmring tal s D projecbahove .the top ot the openings sothat they are .lirinlv embedded in the sand 13 \Yil'lt'it is nowrzunuuul llll During this lumping ol" thewand.

the flash. it is quite prohalrlc that the anchorincur hers 9 aredeflected outu'ardl to some (K- upon the main hodv oi? the .sa 11dWithin the completely tilled with compacted sand. porprint *ascompletedyeonsistsc-o't small sew tions ol sand i embedded iin thesul'iatanco ot', the: retainer deviee.

When-the flaski hasi been. tilled: a nd .propen ly tamped, the section*isfuim'ei'tcd and tent so that the ohtain a 'vcrv ilirui :ui i

tions i of which enter the perforations o t' the. retainer, so that the.outer surl'aeeool' the separated from the board 2 and the pattern 1 iswithdrawn'trom the sand, thus leaving the mold cavity 15. The green sandprints tor-med by the above operation now project into the mold cavity,such prints being retained in proper position by the retainer devices 6which in efi'ect form still and tough outer shells or skins for theprints.

In a similar way the upper section 3 of the flask is provided with amold cavity 15 also having the green sand prints projecting from itswall, such prints being reinforced by retainers in the manner justdescribed.

A core ll) of suitable shape is made in the usual manner, such corebeing provided atthe proper points with shallow socket openings 16corresponding in number and position to the prints provided as abovedescribed. The niolder now takes this core and sets its lower socketopenings 16 over the inner ends of the reinforced green sand printsprojecting up into the lower half 15 of the mold cavity. It necessary.chaplets l7 and 17" of any desired type may be introduced at the propertime in the operation to provide additional supports for the core.

The molder now disposes the inverted upper half of the flask upon thelower half in such manner as to cause the reinforced green sand printswhich project from the inner surface of the upper mold cavity 15 toregister with the socket openings 16 at the upper side of the core.

As above stated such shallow socket openings 1h maintain their accuracyof shape and position after baking much better than does the usual coreprint. Since the core is quite stiff, as are also the reinforced prints,these sockets may be relied upon as a means for locating the core.

in accordance with the present invention the green sand prints havingthe stifl' and rigid outer skins or shells are capable of withstandinglateral pressure without breaking down or deformation and thus when thesockets ot the core member receive these reinforced prints the core isheld very rigidly in position so that it can not move in a lonaiiudina]direction or toward or from the lateral wall of the mold cavity. Thisrigid support of the core is such and the accuracy of location is sosuperior to ordinary practice that I find it possible to reduce thethickness of the walls of the castings produced by this process, thussaving a considcrable amount of material without unnecessarilysacrificing strength in the finished casting.

The mold, having been completed as just described, the iron is poured inthe usual manner, producing a cored casting such as indicated at 19 inFig. 5. When the casting is removed from the mold the retainer devices 6are found to be united to the casting and project from the latter asindicated in Fig. 5. Since the taper of green sand prints, made as justdescribed, is inwardly of the casting, it may be noted that the openingin the casting tapers inwardly as shown at 21, the: retainer deviceconstituting a lining for this opening.

T he opening may now be finished and the retainer removed as indicatedin Fig. 6 by introducing a tapered milling cutter 22 or other propertool which cuts out the retainer device and produces a smoothly finishedinwardly tapering opening. As the opening in the casting, defined by theretainer device, tapers inwardly, the amount of metal to be removed bythe machining operation is very small as compared with that which wouldnecessarily have to be removed were the o icning made initially with itstaper in the opposite direction. Moreover since the retainer deviceconstitutes a lining for the opening. the cutting tool does notencounter hard particles of slag, embedded sand, or the like. andretains its edge much longer than when used in an unlined opening, itbeing obvious thatundcr some circumstances the presence of thisrelatively smooth and finished lining element may render machiningwholly unnecessary.

In Fig. 8 I have illustrated the result of employing a core print, themain body of the core being indicated at O and the print at P. Themolding sand is indicated at S and the casting at I. In this case it maybe noted that the opening produced in the casting flares inwardly. Toproduce an inwardly tapering opening in such a casting would thusrequire an excess amount of ma chine work.

After the casting has been machined in the manner illust 'ated in Fig. 6it may be associated with a similar casting 19" as indicated in Fig. 7and united thereto by a thim-ble 23 having oppositely tapered portions21 and 21, this method of uniting the sections and the means forconnecting them being old and well known and forming no part of thepresent invention.

\Vhile I have illustrated the invention as applied to the melding of: aradiator section, it is to be understood that the invention is notconfinedto this particular use or environment but that it may be founduse ful in the production of any cored casting in which an opening is tobe provided during the process of casting. Furthermore, in so far as theretainer device is concerned, it is clear that the dimensions andexactshape here shown are not in any sense to be considered as limitingsince such retainer will be made to conform. in any particular case tothe shape and size of the desired print. Moreover, I contemplate thatunder certain circumstances the retainer may form less than a completecircle; that it need not form the outer snr'face of the print but may beembedded more deeply therein than hereinabove described; and that infact the reinforcing of the green sand print may be accomplished broadlyspeaking, in other ways and by the use of other materials than thosehercinabove referred to.

I claim:

I. That process of making molds for cored radiator sections whichcomprise preparing a pattern having spaced print forming cavities,placing: reinforce material in each cavity, embedding the pattern insand, removinnthe pattern to leave a mold cavity hav ing spacedreil'il'orccd green sand prints projecting into it, preparing a corehaving spaced print receiving sockets, and locating the core in the moldcavity by .litti-nP; its socket-s over {he re-pcctive prints.

That process of making molds for cored radiator scctione which comprisesforming; a mold cavity having a. plurality of rspaced sti if and rigidreinii'orced green sand printn projecting into it, providing a corehaving sockets; spaced eimilarl to i-aid prints, and locating thecore inthe mold cavity by fitting its respective sockets over correspondingprints.

That process olfmaking molds for cored castings which comprises as stepsproviding a pattern with an inwardly tapered print forming cavity,lining eaid cavity with reinlorce material, permitting a portion of saidmaterial to project beyond the cavity, cm-, bedding the pattern in sand,ren'ioving the pattern to leave a mold cavity in the sand with a taperedreimlerced green eand print projecting inwardly into the cavity, andengaging a core with the inner end of said print.

4:. A print reinforce device comprising a thin walled shell TlO'l'encloi'iing the sand of a green sandprint, said shell being, ofopenivorlc construction so that the enter riacc of the completed printcoaf ta of email sections of sand embedded in the nnhntancc of theretainer device.

A cup-like retainer of perforated sheet metal for preserving the shapeoi. a green sand print, said retainer lacing provided at one end withanchoring means.

6. A device :lor preeerving the shape oil a green sand print comprieiinra thin walled shell for reinforcing the eiqiioaed isnrlaccr ol theprint, and means or anchoring the device in position.

i. A reinforce device r leei z'nc l to Form an outer skin for a greenrand print. said device conipriein g a cylindrical Willi portionprovided with an inwardi; directed llange atone end adapted to preventthe sand from dropping out of the end of the r:-inl'orco device.

A printing reinjl orce device compriain r a thin metallic :ihell having,a cylindrical wall provided with an inwardly directed radial flange atone end and with anchrn'ing means at its other end.

9. reprinting; reinforce derive comprteinp a. tapered cyliinlrical ahclloi ahcet liltlll'l'llll having a plurality ol. anchoring lair: preparimefrom its larger end.

ll). Apr-int reinforce device comprising a. tapered cup-like shell oilperforated ahcci. material, Said shell having an amnilar inwardlydirected flange at il'i smaller vial and a plurality ofcircmnllercntially Spaced anchoringtabs at its: larger end.

Signed by me at lVestlield, lilasaachneclta, this 30th day of September,1926.

CLARENCE it. re ace.

